Electrode for dielectric-thin film device, and ultrasonic wave oscillator using the electrode

Abstract

An electrode for a dielectric thin film device includes an adhesive layer adhering to a substrate, a diffusion suppressing layer containing compounds of metal elements constituting the adhesive layer or the substrate, and a main conduction layer. The crystallinity is enhanced by preventing diffusion of unnecessary elements into the dielectric thin film.

What is claimed is: 
     
       1. An electrode structure comprising: an electrically insulating film;   a metal adhesive film disposed on the electrically insulating film and including a metal selected from the group consisting of titanium, chromium, tantalum, vanadium, and niobium;   a metal film different in composition from the metal adhesive film, disposed on the metal adhesive film, and including one of an oxide and a nitride of the metal of the metal adhesive film for preventing diffusion of the metal of the metal adhesive film through the metal film; and   a conductor film disposed on the metal film and selected from the group consisting of gold, platinum, iridium, and ruthenium.   
     
     
       2. The electrode structure as claimed in claim 1, wherein the metal film contains atoms of the metal of the conductor film. 
     
     
       3. The electrode structure as claimed in claim 1, wherein the metal film has a portion with a content of the metal of the metal adhesive film, when expressed using a ratio of metal elements only, in a range from more than 0 atomic % to 75 atomic %. 
     
     
       4. The electrode structure as claimed in claim 1, wherein the conductor film is platinum, the metal film includes platinum and titanium oxide, and the metal adhesive film is titanium. 
     
     
       5. An ultrasonic wave oscillator including an electrode structure comprising: an electrically insulating film;   a metal adhesive film disposed on the electrically insulating film and including a metal selected from the group consisting of titanium, chromium, tantalum, vanadium, and niobium;   a metal film different in composition from the metal adhesive film, disposed on the metal adhesive film, and including one of an oxide and a nitride of the metal of the metal adhesive film for preventing diffusion of the metal of the metal adhesive film through the metal film; and   a conductor film disposed on the metal film and selected from the group consisting of gold, platinum, iridium, and ruthenium.